The variables declared in a class for the use of all methods of the class are called reference variablesobjectsinstance variablesNone of these

The correct answer to the question is "instance variables".

Explanation:

1. Reference Variables: These are used to refer to objects but do not specifically indicate variables used for all methods of a class.

2. Objects: An object is an instance of a class that encapsulates data and functionality defined in that class.

3. Instance Variables: These are the variables declared within a class but outside any method, and they hold values that are specific to each instance of the class. They are accessible from all methods of the class.

4. None of These: This option would imply that none of the provided terms accurately describe the variables in question.

Conclusion:

Therefore, instance variables are the correct term for variables declared in a class that can be used by all its methods.